1. Field of the Invention
This application relates to a door lock, and particularly to an electronic door lock which functions both mechanically and electrically.
2. Description of the Related Art
Generally, the designs of door locks are directed towards simplicity, convenience, as well as enhancement for security. A mechanical door lock operated by a key is sometimes inconvenient because the user may not have the key in hand. Although an electric door lock operated electrically is relatively convenient, it will be inoperative in case of power shortages. For efficiency purposes, electric door locks that function mechanically and electrically have been developed. Examples of such electric door locks are disclosed in US Publication Nos. 20070169525 and 20030209042. However, when a latch bolt of such an electric door lock is jammed, a motor to operate the latch bolt will malfunction.